Depending on the type of insufficiency concerned (ulcer, varicose veins, edema, phlebitis, lymphoedema) and the part of the patient's body that is affected thereby, it is common practice on a leg to use a stocking, a long sock, or a short sock, and on an arm to use a sleeve whose length varies according to circumstances, the sleeve optionally being fitted with a shoulder strap.
The state of the art is illustrated by the following documents: FR-A-2 671 485, FR-A-2 654 925, FR-A-2 588 890, FR-A-2 587 617 and CH-A-675 201.
In addition to the therapeutic effect produced by applying compression to the limb concerned, such various remedial support appliances must be as tolerable as possible by the patient.
It has been observed that patients already traumatized by the state in which they find themselves actually wear prescribed remedial support appliances on a regular basis only when they are sufficiently comfortable, with the sensation of comfort being both physiological (e.g. in the event of the appliance slipping down and/or creasing) and psychological (the traumatic aspect of fastening means that are bulky and/or complicated).
The problem of the appliance slipping down progressively is particularly important, not only because such slippage is disagreeable for the patient (physiologically because it feels uncomfortable, and psychologically because it looks unattractive), but also because its therapeutic effect is reduced under such circumstances.
In the particular case of elastic stockings (when the patient cannot or will not wear elastic tights), it is present practice to use fastening and support means derived from traditional underwear (e.g. suspenders), or else adhesive means. Suspenders or braces are indeed effective, but in addition to being outdated, such systems remain constraining, uncomfortable, and visible through fitted clothing. Adhesive applied directly to the skin, even when washable in water, is difficult for patients to accept both for physical reasons and for psychological reasons that will readily be understood.
For sleeves designed to treat edema of the arm, particularly in the context of breast surgery and/or cobalt therapy, it is conventional to use a fastening system that includes a strap passing beneath a breast to be fastened on the side, and this often has a traumatic effect on people already shocked by the treatment to which they have been subjected.
It might be tempting to look for inspiration in the antislip systems that are to be found in hosiery for everyday stockings, which are based on the principle of a tight top band that is covered on the inside with one or two circumferential lines of silicone.
In hosiery stockings fitted with such an antislip band, the top band used is elasticated and its component fibers are selected so that said band exerts pressure on the thigh that is very much greater (generally at least three or four times greater) than the very low pressure that is exerted by the stocking proper: since medical elastic stockings are designed to improve return circulation, there can be no question of using a top band designed in that way since that would constitute a kind of tourniquet around the upper thigh specifically at the level of the saphenous vein. In addition, the antislip system based on an elasticated band and used for hosiery stockings generally presents an elongation characteristic having a steep slope, e.g. corresponding to 5% to 7% elongation per Newton exerted in traction, thereby giving rise to large variations in exerted pressure for a given size of stocking depending on the circumference of the thigh: this also goes against the effect that is required of an elastic stocking where it is absolutely essential to avoid any risk of strangulation of the limb concerned.
As a result, the teaching of hosiery stockings appears, a priori, to be of no help in solving the problem posed.
Such attempts may be illustrated by the three following documents.
Document DE-U-82 17 651 describes an elastic stocking whose main portion is extended upwards by an elasticated garter band. The garter band is implemented in the form of a tape made on a crochet machine and covered on its inside with antislip segments or stitches provided in discontinuous manner. Provision is made firstly for the tape to have the same elongation characteristic as the main portion of the stocking in the vicinity of said tape, and thus a characteristic of steep slope (in a diagram where traction force is shown as a function of percentage elongation), and also exerts the same pressure as said main portion.
Such a tape therefore constitutes an extension of the therapeutic action of the stocking, and gives rise to a risk of strangulation, which although smaller than that associated with hosiery stockings is nevertheless sufficient for a stocking of that type to be considered as providing poor performance as a medical elastic stocking.
Document FR-A-2 302 054 describes an elastic stocking fitted with an elasticated garter band fixed to the main portion of the stocking by means of an overcast seam. The garter band is constituted by elasticated cloth covered on the inside over substantially its entire height by means of a grooved elastomer. Such a covering which is said to be non-slip, does not provide effective protection against slipping since, with the allowable amount of thickness (excessive-tightness would give rise to a rise of strangulation), it adheres insufficiently to the skin. In addition, that document gives no teaching on the choice of an elongation characteristic and/or on a special pressure to be exerted by the garter band, but gives teaching only with respect to avoiding the tourniquet effect at the seam securing said band so as to avoid marking the skin.
Finally, document U.S. Pat. No. 3,800,331 describes a stocking that applies uniform pressure (i.e. pressure that is not degressive) and that is fitted with an antislip band formed by alternating annular zones knitted with a springy elasticated thread, and transition zones having a vertical thread. It is specified that the diameter of the band is selected to be equal to or greater than the diameter of the main portion of the stocking in the vicinity of said band. Using such teaching that consists in selecting the length of the band (when flat) for the purpose of adjusting the pressure that is exerted, no attention is paid to the elongation characteristic thereof such that the tightness exerted by the band may be excessive. Doubtless that is the reason why such a stocking is usable only when made to measure, as is specified in the document. As a subsidiary point, the antislip band includes projecting elasticated threads on its inside, and this constitutes a source of discomfort (in particular because the threads tweak hairs).